Submerged combustion heat-generator, in particular for the production of very hot water

ABSTRACT

A submerged combustion heat-generator enabling the obtention of a high-temperature heat-carrying fluid. The heat generator of the invention uses a burner operating on combustion in a liquid bath, for instance of water and the combustion gases burn in a combustion chamber which is at least partially immerged in the said bath and at least partially heat-insulated therefrom. Said combustion chamber comprises a second heat-exchanger which is mounted upstream of said first exchanger on the heat-carrying fluid path.

United States Patent Glachant et al.

[54] SUBMERGED COMBUSTION HEAT- GENERATOR, IN PARTICULAR FOR THE PRODUCTION OF VERY HOT WATER Inventors: Luc Clement Dominique Glachant, Brunoy; Remi Pierre Leon Alain Guillet, Saint Mande, both of France Assignee: Gaz de France, Paris, France Filed: Nov. 30, 1970 Appl. No.: 93,767

Foreign Application Priority Data Nov. 28, 1969 France ..6941280 US. Cl ..126/360 A, 165/104, 165/145 Int. Cl. ..F24h I/l0, F280 3/00 Field of Search ..165/1 1 l, 104; 126/260 A; 122/31 A 1 Sept. 19, 1972 [56] References Cited UNITED STATES PATENTS 3,060,921 10/1962 Luring et a1 ..126/360 A X 2,594,234 4/1952 Swindin ..126/360 A 1,869,340 7/1932 Mann,.lr ..165/1ll X 3,138,150 6/1964 Hyer et a1. ..l26/360 A 3,368,548 2/1968 Santoleri et a1 ..126/360 A Primary Examiner-Albert W. Davis, Jr.

Attorney-Kenyon & Kenyon Reilly Carr Chapin [57] ABSTRACT A submerged combustion heat-generator enabling the obtention of a high-temperature heat-carrying fluid.

4 Claims, 2 Drawing Figures SUBMERGED COMBUSTION HEAT-GENERATOR,

IN PARTICULAR FOR THE PRODUCTION OF VERY HOT WATER The present invention has essentially for its object a submersed combustion heat-generator enabling the obtention of a high-temperature heat-carrying fluid. The heat generator of the inventionis of the type using at least one burner, in particular a gas burner, operating on submersed combustion in a liquid bath, for instance a water bath.

Owing to their design, the heat-generators provided with a conventional heat exchanger and used to raise the temperature of the heat-carrying fluid to the level which is most convenient for usual applications, seldom exceed 70 to 80 percent efficiency alloys, on the gross heat value (GI-IV) of the fuel used, Le. 80 to 90 percent calculated on the net heat value (NI-IV).

Some of the devices call submersed combustion devices wherein the combustion takes place within the bath to be heated thus leading to particularly favorable exchange conditions, enable to reach efficiencies higher than or at least equal to 90 percent calculated on the I-lI-lV (100 percent calculated on the NHV), as far as the bath temperature is lower than or, in any case, at most equal to the dew temperature of the combustion products of the fuel involved.

The dew temperature of thecombustion products therefor appears asa limiting factor for the advantage offered by submersed combustion. For instance, the dew temperature of the Lacq gas combustion products approximates 60 C. Under such conditions, in the case considered, the normal, submerse combustion of the Lacq gas is not usable and in fact is not used unless the bath is maintained at a temperature lower than 60 C, this being the maximum temperature of the heat-carrying fluid used for deriving heat energy at the level of the bath.

According to the improvements forming the subject matter of the present invention, it is thereforepossible to produce very hot water or even vapor while atthe same time retaining the advantage of the efficiency of the submersed combustion effected within a relatively low temperature bath.

The heat generator according .to the invention, which enables to obtain the above-mentioned purpose, is characterizednotably in that the heat supplied by the combustion gases to the said bath being draw off, for use, by at least a first heat exchanger which is advantageously immersed (partially or completely) in the said bath, there is provided a combustion chamber which is at least partially heat-insulated form the :said bath, wherein the combustion gases burn and which comprises a second gas/heat-carrying fluid heatexchanger which is placed on the path of the said heatcarrying fluid after the said first immersed exhanger. Advantageously, the second exchanger is constituted by a boiler body, in a manner known per se.

Thus, by selecting the relative dimensions of the boiler body it is possible to raise as much as desired the temperature of the heat-carrying fluid, while at the same time retaining the advantages of submersed combustion the fumes, before escaping to atmosphere, bubble in a water bath whose temperature may be selected sufficiently low to profit by the high efficiency of the submersed combustion as mentioned previously. In particular, if the bath temperature is lower than the dew temperature of the fumes, it is possible to obtain an efficiency higher than C calculated on'the GHV of the plant. The only necessary condition is that the heat-carryingfluid should enter the plate at a temperature lower than the dew temperature of the fumes.

Other features, purposes and advantages of the invention will appear more clearly from the following description made with reference to FIGS. 1 and 2 of the drawings illustrating diagrammatically and by way of non-limitative example two plants designed according to the invention.

According to the form of. embodiment of a plant il- .lustrated in FIG. 1, thecombustiible mixture is conveyed through conduits 10, 11 into a combustion chamber 12 which is immerged in awater bath 13 contained in a container 14. The chamber 12 is in the form of a vertical cylindrical boiler body closed at its top by a wall 15. The chamber 12 is constituted internally by an exchanger 16 through which the heat-carrying fluid passes. The exchanger 16 may be constituted by an annular water sheet surrounding the flame, by tubes ar ranged in parallel relationship to the generating lines of the chamber 12, or again, for instance, by tubes arranged as coils. The upper wall l5 and the side wall 17 of the boiler body thermally insulate the chamber 12 from the bath 13. The combustible mixture burns at least partially in the chamber l2fand the combustion products issuefromthe open top of the chamber and bubble in the bath 13.

The heat-carrying fluid penetrates at 18 in the cold state, passes through ansexchanged l9. immersed in the bath l3 and then enters the exchanger 16 contained in the combustion chamber 12. The heat-carryingfluid issues from the plant at 20 in the hot state. If the heatcarrying fluid is water, there may be obtained at 20 water orvapor at. a temperature and under a pressure as high as desired.

As mentioned previously, the temperature of the bath 13 is maintained below the dew temperature of the combustion products of the combustible mixture, a total efficiency of the plant equal or higher than 90 percent calculated on the GHV may be obtained provided the heat-carrying fluid enters at 18 in a sufficiently cold state to enable the caloriesleft in the bath 13 by the submersed combusion to be drawn off.

The harmful products of combustion such as for instance SO CO Lare drawn off continuously from the bath .13 through conduit 21 and may be conveyed into a regenerating apparatus 22 operating according to a closed loop. as shown in 23.

In a modified form of embodiment illustrated in FIG. 2, there is shown a plant which is a littlemore complex than the previous one. In this Figure, the numbers oarrying the sign have been used to indicate the similar components found in the plants of both Figures.

A basic difference between the plants of FIGS. 1 and .2 is that the container 14' is maintained under pressure. This enables to raise the temperature of the bath 13'.

in the name of the same applicant and entitledSubmerged combustion heat-generator.

Advantageously and as described in the said patent application, the fumes issuing at 21' under pressure bubble in a condenser-regenerator 24 which is subjected to substantially the same pressure (except for the pressure losses in the conduit 21) and wherein the latent heat of water condensation of the fumes under pressure is left.

Under such conditions, the heat-carrying fluid penetrates at in the cold state, is heated in an exchanger 26 immersed in the he hath 27 of the water condensed in the condenser 24, and then penetrates at 18 to pass successively through the exchanger 19' and the tubes 16' and issue in the hot state at 20. Condensed water from the condenser 24 is conveyed by a pump 28 and a conduit 29 back into the bath 13' so as v to compensate for the water vapor carried along in the fumes 21' subsequent to the submersed combustion under pressure.

A great number of modifications may be effected in the forms of embodiment which have just been described. In particular, as described in the aforementioned patent application, it may be useful to provide for several steps of condensation and regeneration arranged in series, the bath temperatures of which are stepped below that of the bath l3 and the pressures of which are substantially the same (except for pressure losses).

In this case, the generator as a whole is similar to a dry fume boiler with a very high efficiency, which is particularly suitable for heating water to a high temperature and which allows for substantial differences between the input temperature and the output temperature of the heat-carrying fluid.

There may be provided in the fume escape circuit an expansion turbine, the energy of which may be used for instance for the compression of the combustible mixture and in particular of the combustive gas for submersed combustion.

Of course, the invention is by no means limited to the forms of embodiment described and illustrated, which have been given by way of example only the invention comprising all technical equivalent to the means described as well as their combinations, should the latter be carried out according to its spirit.

What is claimed is:

l. A plant for heating a heat-carrying fluid circulated in said plant comprising: (1) a heating chamber, (2) a first bath of water wherewith said chamber is at least partially filled, (3) a burner operating at least partially on submersed combustion in said bath of water, (4) means for supplying said burnerwith a combustible mixture under pressure, (5 a combustion chamber immersed in said first bath of water and at least partially heat-insulated from it wherein said burner is mounted and wherein the combustible mixture burns at least partially prior to submersed combustion, (6) a first heat exchanger immersed in said first bath of water and through which is circulated said heat-carrying fluid for draining out from said bath of water the calories generated and left by the combustion of said combustible mixture in said heating chamber and by the bubbling of the combustion products through said bath of water, and (7) a gas/heat-carrying fluid heat exchanger placed in said combustion chamber on the path of the said heat-carrying fluid just before its issuance from the plant, after its passage trough said first heatexchanger.

2. A plant according to claim 1 further comprising: (8) a condenser, (9) a second bath of water wherewith said condenser is at least partially filled, (10) a second heat exchanger immersed in said second bath of water, (1 1) means for returning water from said second bath the said first bath, (12) an inlet in said condenser for the combustion products generated in said heating chamber, (13) conduit means connecting the exhaust of combustion products issuing from said heating chamber to said inlet of combustion products supplied to said condenser, 14) an outlet in said condenser connected to the atmosphere and (15) connecting and pumping means for circulating said heat-carrying fluid successively into said second heat-exchanger and into said first heat-exchanger in which said fluid is progressively heated from its supplying into the plant up to its supplying to said gas/heat-carrying fluid heat exchanger before its issuing from the plant.

3. A plant according to claim 1, wherein the said gas/heat-carrying fluid exchanger is constituted by a boiler body.

4. A plant according to claim 1, wherein said combustion chamber immersed in said first bath of water is cylindrical, substantially vertical and its inner wall is constituted by said gas/heat-carrying fluid exchanger which is subjected to the action of the combustion products.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 .692,017 Dated Sept. 19, 97

Luc Clement Dominique Glachant and 1 v Remi Pierre Leon Alain Guillet It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

In the Title SUBMERGED Should read --S ubmersed--- In the ABSTRACT line 1, "submerged" should read --submersed--- In the ABSTRACT line t insert ---submersed--- before "combustion" In Col. 1, line 15, insert ---calculated--- after "efficiency"; same line, delete alloys,

In col. line 2 "HIV" should read ---GHV---3 In col. line 33 "submerse" should read --submersed--;

In col. line 56 "exhanger" should read --exchanger--;

line 57, insert -'---'-said---- before "second";

In Col. line l, "plate" should read --plant--;

In Col.

In col. 1

2 line 33, "exchanged" should read --exchanger-- In Col. line 66, "96,799" should read ---96,766---;

In Col. 3, line 10, delete "he" In Col. line 26, "the" should read ---to---.

Signed and sealed this 6th day of February 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,J'R. ROBERT GO'ITSCHALK Attesting Officer Commissioner of Patents FORM PO-105O (10-69) uscomwoc eos7e-pbw U5. GOVERNMENT FRINTlNG OFFICE I 19" 0-16 1 

1. A plant for heating a heat-carrying fluid circulated in said plant comprising: (1) a heating chamber, (2) a first bath of water wherewith said chamber is at least partially filled, (3) a burner operating at least partially on submersed combustion in said bath of water, (4) means for supplying said burner with a combustible mixture under pressure, (5) a combustion chamber immersed in said first bath of water and at least partially heatinsulated from it wherein said burner is mounted and wherein the combustible mixture burns at least partially prior to submersed combustion, (6) a first heat exchanger immersed in said first bath of water and through which is circulated said heat-carrying fluid for draining out from said bath of water the calories generated and left by the combustion of said combustible mixture in said heating chamber and by the bubbling of the combustion products through said bath of water, and (7) a gas/heat-carrying fluid heat exchanger placed in said combustion chamber on the path of the said heat-carrying fluid just before its issuance from the plant, after its passage through said first heatexchanger.
 2. A plant according to claim 1 further comprising: (8) a condenser, (9) a second bath of water wherewith said condenser is at least partially filled, (10) a second heat exchanger immersed in said second bath of water, (11) means for returning water from said second bath the said first bath, (12) an inlet in said condenser for the combustion products generated in said heating chamber, (13) conduit means connecting the exhaust of combustion products issuing from said heating chamber to said inlet of combustion products supplied to said condenser, (14) an outlet in said condenser connected to the atmosPhere and (15) connecting and pumping means for circulating said heat-carrying fluid successively into said second heat-exchanger and into said first heat-exchanger in which said fluid is progressively heated from its supplying into the plant up to its supplying to said gas/heat-carrying fluid heat exchanger before its issuing from the plant.
 3. A plant according to claim 1, wherein the said gas/heat-carrying fluid exchanger is constituted by a boiler body.
 4. A plant according to claim 1, wherein said combustion chamber immersed in said first bath of water is cylindrical, substantially vertical and its inner wall is constituted by said gas/heat-carrying fluid exchanger which is subjected to the action of the combustion products. 